This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The mechanisms regulating constriction and relaxation of vascular smooth muscle in healthy and diseased blood vessels are incompletely understood, but the activation of one or more phospholipases leading to the initial release of arachidonic acid and lysophospholipids play prominent roles.